3D Model Enhances Human Glia conversion to Neurons with Dopaminergic Functional and Molecular Traits Or: 3D Model Enhances Human Glia conver-sion to Induced Dopamine Neurons?

Parkinson’s disease (PD), a prevalent neurodegenerative disorder, is primarily characterized by progressive loss of ventral midbrain dopamine (DA) neurons. This focal degeneration makes PD suitable for cell replacement therapies and clinical trials using stem cell derived-DA neurons are ongoing. An emerging alternative to cell transplantation for brain repair is in vivo reprogramming, where resident glia is converted into neurons directly inside the brain. While functional neurons with potential therapeutic effects can be obtained via in vivo conversion in rodent studies, translating this to relevant human pre-clinical models has been limited to two-dimensional (2D) cultures. To mimic three-dimensional (3D) complexity and approximate in vivo-like conversion, we developed a 3D model for human glia conversion. Our model promotes neural conversion and generates functionally mature DA neurons at a faster pace than in 2D. Molecular profiling, single-nucleus transcriptomics and lineage tracing mapped glia heterogeneity, provided mechanistic insights of the reprogramming process and defined neuronal identity after conversion. Our results emphasize the advantages of utilizing 3D models as a reproducible and con-sistent platform for reprogramming studies.